2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/86658An explicit and remarkably simple one-dimensional integral expression is derived for the mean number $<N>$ of photons emitted per revolution in synchrotron radiation. The familiar high-energy expression $5πα/\sqrt{3(1-β^2)}$, printed repeatedly in the literature, is found to be inaccurate and only truly asymptotic with relative errors of 160%, 82% for $β=0.8$, 0.9, respectively. A new improved high-energy expression for $<N>$ is given.LaTeX, 3 pages, no figureAccelerator Physicstext